Optical coherence tomography (OCT) is an optical method, with which images can be produced from inside vessels. Such a method is known from example from WO 97/32182 A1.
To produce images, a catheter is inserted into the vessel. At the tip of the catheter, rotating about a catheter axis, light in the light wave range of around 1,300 nm is emitted onto the surrounding vessel wall. The light reflected in the region of the vessel wall is detected and evaluated using interferometry. As a result it is possible to produce a two-dimensional image, which provides information about the vessel wall with depth resolution. If the catheter is also displaced in the vessel parallel to the catheter axis, a number of such two-dimensional images can be recorded in a continuous manner. A three-dimensional image can be generated from the number of two-dimensional images.
However the production of images using OCT requires that the blood contained in the section of the vessel to be examined is removed therefrom. To this end the vessel can be sealed using a balloon provided on the catheter or on a further catheter. Such a catheter is for example known from EP 0 330 376 A2. When the vessel has been sealed, the blood contained therein is displaced by means of a rinsing fluid, which is delivered into the vessel by the catheter or the further catheter. A separate injection device is provided to deliver the rinsing fluid.
If the vessel to be examined is part of the heart for example, the required sealing or occlusion of the vessel can cause cardiac activity to be disrupted. It is therefore necessary to seal the vessel to be examined for as short a time period as possible.
According to the prior art, separate devices have to be operated by the treating doctor and their assistants to carry out an examination using OCT. The balloon is generally inflated manually using a pump. An injector or fluid pump has to be operated to deliver the rinsing fluid. A displacement device has to be operated to rotate the OCT catheter and/or displace it in an axial manner. Operation of the above-mentioned separate devices requires team coordination and skill. If the devices are not operated in an optimum manner, the time period for which the vessel is occluded has to be extended in an undesirable manner.